People blink as many as 15 to 20 times a minute, far more than needed to keep our eyes lubricated. So why do we do it?

A new paper posits that our constant fluttering is actually a form of wakeful rest, or a mental break between thoughts. Researchers discovered that when people blink, brain activity spikes in areas associated with such brief reprieves, improving our ability to tune in to our current activities.

The study was born from the observation that human blinking is not random but actually predictable from person to person. People watching the same movie, for example, tend to blink at the same time.

The research sets a blueprint for future studies on just where our mind goes each time we close our eyes.

Correction, Dec. 26:An earlier version of this video said people blink 15 to 20 times a second.